27 : 18 = 13 : x find x

 27:18 and 13:x can also be written as 27/18 and 13/x

therefore, 27:18 = 13:x

                 27/18 = 13/x

                 27/18 *13= x

               x = 19.5

Hope it helped u,

pls mark as the brainliest

and put thanks

^_^

expression #3 is not equivalent. the others are.